1906.] Mr. H. F. Newall on Eclipse ProUems. 231 



WEEKLY EVENING MEETING, 



Friday, February 9, 1906. 



The Right Hon. Lord Alverstone, G.C.M.G. M.A. LL.D. F.R.S. 

 Vice-President, in the Chair. 



Hugh Frank Newall, Esq., M.A. F.R.S. 



Eclipse ProUems and Observations. 



The title of my lecture to-night is " Eclipse Problems and Obser- 

 vations," not " Problems and their Solutions," though we may hope 

 that we have made steps towards solutions. If my remarks seem to 

 be somewhat vague and speculative, I claim your indulgence, for is 

 not wonder the first step to knowledge ? Wonder and speculation 

 are very much akin. 



The fact that more than eighty expeditions of various nationali- 

 ties were organised to observe the eclipse of the sun in August 1905, 

 is evidence of very keen interest in the phenomena to be observed 

 during an eclipse. If one searches for reasons for this growing 

 interest, it seems not improbable that it is connected with the dis- 

 coveries with which physicists have been astounding us in the 

 domain of electricity and radiation. No one who grasps, in even a 

 dim way, the enormous advances in our knowledge of the minute pro- 

 cesses involved in electrical discharge and of the by-products of the 

 mechanism of the incandescence of glowing bodies can fail to see what 

 a superb opportunity is afforded by eclipses of the sun to students of 

 physics who are interested in the application of knowledge gained in 

 the laboratory to cosmical phenomena. Who can look at the wondrous 

 beauty of the corona — that delicate radiance which is disclosed round 

 the sun when the opaque body of the moon moves in front of the 

 sun and cuts off the bright light of day from the eyes of the 

 observer, and also from the air and the sky round about — who, I ask, 

 can look at the corona, without the thought that many of the long 

 rays and streamers which seem to emanate from the sun must be 

 stretching out towards the earth, and bringing with them possible 

 influences of which he would fain know the significance ? And yet, 

 who can say that we are anywhere near a clear understanding of the 

 mysteries of the corona ? 



I propose, in the earUer part of my remarks, to do what I may 

 call " sowing seed," by calling your attention to various points in our 

 knowledge of physics, and, towards the end of my lecture, I shall 



